Air and fuel preheating oil burner



Oct. 31, 1944. r w. ROBERTS AIR AND FUEL PREHEATING OIL BURNER Filed June 20. 1942 ATTORNEY.

Patented oct. 31, 1944 NT; oFF c Amish PREHEATING on; BURNER William Roberts, Bmtksn, N. Y. Application June 20, 1942; Serial No. 447,860

1 Claim.

The invention relates to oil burners in which the fuel under pressure is delivered by aspray nozzle at the end of the fuel line into the airblast leaving the discharge barrel.

The object of this invention is to improve the combustion of this type of oil burner.

This object is achieved by providing means for preheating air and fuel.

The air is heated to a temperature above the boiling point of the fuel by forcing the airblast to pass through a housing the walls of which are heated by combustion.

The fuel is heated to a temperature at which the fuel in the end of the fuelline is still maintained in liquid state by conducting part of the heat absorbed by said housing to the spray nozzle at the end of the fuel line.

By providing within said housing a combustion chamber through which passes the heated airblast and by placing the spray. nozzle in a wall constituting the wall of said combustion chamber, facing the discharge barrel, part of the heat absorbed by this wall is conducte to the spray nozzle.

As the tip of the spray nozzle and one side of this wall are exposed to the heat of combustion and subjected to heat transfer by radiation and as the other side of this Wall, the fuel line and part of the spray nozzle are subjected to heat absorption by the airblast, the temperature of this wall and therewith the temperature of the spray nozzle will not exceed the boiling point of the fuel, so that the fuel under pressure is maintained in liquid state in the fuel line.

The burner starts its normal operation by the conventional means. After a short period of operation combustion greatly improves, raising the initial temperature in the furnace, reducing the percentage of heat loss and maintaining combustion at greatly enlarged flame volume.

I attain this object by the novel combination of various parts and elements fully described in this specification and illustrated in the accompanying drawing in which:

Fig. 1 represents a partly sectional top view of the generator along lines I-| in Fig. 2.

Fig. 2 is a section of the generator.

Fig. 3 is a sectional end view of the same.

The generator is provided with a rim I. which is fitted on the end of the discharge barrel 2.

The ring-shaped housing 3 embodies an outer wall 1, while the part 5 is provided with an inner wall 4. Surface 6 of top part 5 contacts the upper rim of wall I.

The fuel receiving chamber 8 is situated between the inner wall 4 of housing 3 and a deflector 9 connected by ribs l with the outer wall 1 of housing 3.

The ainblast leaving the discharge barrel 2 enter the housing 3 between the deflector 9 and the outer wall 1, passes through chamber H, reverses its direction of flow in the curved top-part 5, enters chamber l2 and passes out of chamber I?! along deflector 9 into the lower part of the fuel receiving chamber 8 which is situated near to the end of discharge barrel 2.

To the end of fuel line I4 is attached the spray nozzle l3 which is inserted in a cap l5 of nonconductive, fireproof material and provided with curved surface IT. Cap I5-is removably fitted in opening l6 of the deflector 9.

Fuel line H and the electrodes I8, l9 are supported in a bracket 20 slideably fitted in the discharge barrel.

The tips 2|, 22, of electrodes l8, [9 pass through cap I5 of non-conductive-flreproof material.

Fuel line I4 with spray nozzle I3, the electrodes l8, 19 with cap and bracket 20 as a unit are removable from the discharge barrel in the conventional manner without afiecting the mounting of the generator at the end of the discharge barrel.

In the open end of the fuel receiving chamber 8 is placed a ball-shaped deflector 23 supported by arms 24, 25 on the walls of housing 3.

Combustion is started by ignition in chamber 8 and the flame leaves the generator through the ring-shaped opening 26 between ball 23 and wall 4 of housing 3.

The burner to which the generator is attached starts combustion with yellow flame, the colour of which changes to bllleish-White after a few minutes of operation.

During operation the generator is kept at medium high temperature by the airblast which will absorb most of the heat transmitted to the generator walls by the heat of combustion, when passing. through the generator.

This feature insuring a long life for the gen erator is not obtainable by devices of this kind in which a mixture of air and fuel is preheated, which mixture cannot be prevented from burning within the generator, when the walls of the latter have reached a temperature above the flash point of the fuel, so that a generator of this type is internally and externally exposed to the heat of combustion with no cooling efiect by theairblast.

The efiicient operation of this generator depends on its preheating effect on the airblast and the temperature of the airblast leaving the generator is relative to the size of the area of the walls exposed to the heat of combustion with which the air is contacting within the generator.

This area is largest in a generator provided with a housing of ring-shaped design as shown in the drawing.

The invention by providing means for preheating air and fuel by the heat of combustion generated during operation greatly improves the combustion of the oil burner of the pressure atomizing type and reduces its fuel consumption 30-40% without requiring any change of its design. The characteristic feature of this invention is based on the means for preheating the air to a temperature above and the means for preheating the fuel to a temperature below the boiling point of the fuel which means may be altered in shape and design without departing from the spirit of this invention.

I claim:

In an oil burner, the combination of an air blast conduit; a housing having an outer wall connected to said conduit, and end wall and a reentrant inner wall provided with an opening in alignment with said conduit; a cup-shaped deflector in said housing and extending into the space between said outer and inner walls of the housing to define air passages from said blast conduit to the housing end wall and from the latter wall to said opening; and an oil spray nozzle extending through the bottom of said deflector in alignment with said opening.

WILLIAM ROBERTS. 

